Originally conceived to follow the UK Prestel specifications, and developed on contract by a small UK company called Systems Designers Ltd (originally merged into EDS and now part of HP) for IBM Germany. Btx added a number of additional features before launch, including some inspired by the French Minitel service, to create a new display standard of its own, which in 1981 was designated the CEPT1 profile. A trial system was installed in Düsseldorf and Berlin in 1980.
In 1995 an enhanced backward-compatible standard called Kernel for Intelligent Communication Terminals (KIT) was announced, but this never really gained acceptance. CEPT permits the transmission of graphical pages with a resolution of 480 by 250 pixels, where 32 out of a palette of 4096 colors could be shown at the same time. This corresponds to the technical possibilities of the early 1980s.

Btx always transferred whole screen pages; the receiver paid per received page. The content provider was free to set the price, and could require either a fee per page (0.01 DM to 9.99 DM), or a time-dependent fee (0.01 DM to 1.30 DM per minute).

The last Btx access was switched off at the end of 2001 by Deutsche Telekom; it had been made obsolete by the Internet. However, Btx formed the basis of T-Online, Deutsche Telekom's online service, which maintained a Btx interface in its access software after the T-Online brand was introduced in 1995.